Introduction To Physics

First, the world of the extremely large, the universe itself, Radio telescopes now gather information from the far side of the universe and have recently detected, like radio waves, the “firelight” of the big bang which probably started off the expanding universe nearly 20 billion ‘years ago‘. Second, the world of the extremely small, that of the particles such as electrons, protons, neutrons, mesons and others. The third frontier is the world of complex matter; lt is also the World of “middle-sized” things, from molecules at one extreme to‘ the Earth at the other. This is all fundamental physics, which is the heart of science. ”

But what is physics? According to one definition, physics deals with the study of matter .and energy and the relationship between them. The study of physics involves investigating such things as the laws of motion, the structure of space and time, the nature and type of forces that hold different materials together, the interaction between different particles, the interaction of electromagnetic radiation with matter and soon.

By the end of 19“‘_ century, many physicists started believing that everything about physics has been discovered. However, about the beginning of the twentieth century, many new experimental facts revealed that the laws formulated by the previous investigators need modifications. Further researches gave birth to many new disciplines in physics such as nuclear physics which deals with atomic nuclei,

The measurement of a base q.uantity involves two steps first, the choice of a standard, and second, the establishment of a procedure for comparing the quantity to be measured with the standard so that a number and a unit are determined as the measure of that quantity.

An ideal standard has two principal characteristics-:’it“ is, accessible and it is invariable. These two requirements are often incompatible and a compromise has to be made between them. ‘

The Levels Of Organization of Biology

In order to understand the various phenomena of life, biologists study biological organization at different levels, which are as follows.

1. Subatomic and Atomic level :

All types of matter are made up of elements and each element contains a single kind of atoms (‘a’: not, ‘tom’: cut). The atoms are actually made up of many subatomic particles. The most stable subatomic particles are electrons, protons and neutrons. Out of the 92 kinds of elements that occur in nature, 16 are called bioelements. These take part in making the body mass of a living organism (Figure 1.2). Out of these bioelements; Only six (O, C, H, N, Ca, & P) make 99% of the total mass. Other ten (K, S, Cl, Na, Mg, Fe, Cu, Mn, Zn, & I) collectively make 01% of the total mass.

2. Molecular-level

In organisms, bioelements usually do not occur in isolated forms rather they combine through ionic or covalent bonding. The stable particle formed by such bonding is called a molecule or biomolecule.

An organism is formed by the enormous number of biomolecules of hundreds of different types. These molecules are the building material and are themselves constructed in great variety and complexity due to specific bonding arrangements. Biomolecules are classified as macromolecules and macromolecules. Micromolecules are with low molecular weight e.g. glucose, water etc. and macromolecules are with high molecular weights e.g. starch, proteins, lipids etc

3. Organelle and Cell level

Biomolecules assemble in a particular way and form organelles. The organelles are actually subcellular structures and when they assemble together, units of life i.e. cells are formed.

Each type of organelle is specialized to perform a specific function. For example; mitochondria are specialized for cellular respiration and ribosomes are specialized for protein synthesis. In this way, functions of the cell are accomplished by these specialized structures. It is an example of the division of labour within the cell.

In the case of prokaryotes and most protists, the entire organism consists of a single cell. In the case of most fungi, all animals and all plants, the organism consists of up to trillions of cells.

4. Tissue level

In multicellular organisms, similar cells (performing similar functions) are organized into groups, called tissues. We can define a tissue as a group of similar cells specialized for the performance of a common function. Each cell in a tissue carries on its own life processes (like cellular respiration, protein synthesis), but it also carries on some special processes related to the function of the tissue. There are different types of plant tissues e.g. epidermal tissue, ground tissue, etc. Animal tissues are also of different types e.g. nervous tissue, muscular tissues etc.

5. Organ and Organ system level

In higher multicellular organisms more than one type of tissue having related functions are organized together and make a unit, called organ. Different tissues of an organ perform their specific functions and these functions collectively become the function/s of that organ. For example, the stomach is an organ specialized for the digestion of proteins and for storing food. Two major types of tissue are present in its structure. Epithelial (glandular) tissue secretes gastric juice for the digestion of proteins.

Muscular tissue performs contractions of stomach walls for grinding of food and moving food to the posterior end. So two tissues perform their specific functions, which collectively become the function of the stomach.

The next level of organization in multicellular organisms is the organ system level. Different organs performing related functions are organized together in the form of an organ system. In an organ system, each organ carries out its specific function and the functions of all organs appear as the function of the organ system. For example, the digestive system is an organ system that carries out the process of digestion. Major organs in its framework are oral cavity, stomach, small intestine, large intestine, liver, and pancreas. All these organs help in the process of digestion.

The organ system level is less complex in plants (e.g. root system) as compared to animals. This is due to a greater range of functions and activities in animals than in plants.

6. Individual-level

Different organs and organ systems are organized together to form an individual or organism. In organism, the functions, processes and activities of various organs and organ systems are coordinated. For example, when a man is engaged in continuous and hard exercise, not only his muscles are working but also there is an increase in the rate of respiration and heartbeat. This accelerated rate of respiration and heartbeat supplies more oxygen and food to the muscles which they need for continuous work.

7. Population-level

Biologists extend their studies to the population level where they study interactions among the member of the same species living in the same habitat. A population is defined as a group of organisms of the same species located at the same place, in the same time. For example, the human population in Pakistan in 2010 comprises of 173.5 million individuals (according to the Ministry of Population Welfare, Government of Pakistan).

A species is defined as a group of organisms capable of interbreeding and producing fertile offspring.

Habitat means the area of the environment in which organism lives.

8. Community Level

A community is an assemblage of different populations, interacting with one another within the same environment. A forest may be considered as a community. It includes different plant, microorganisms, fungi and animal species. Communities are collections of organisms, in which one population may increase and others may decrease. Some communities are complex e.g. a forest community, a pond community etc. Other communities may be simple e.g. a fallen log with various populations under it. In a simple community number and size of populations is limited. So any change in biotic or abiotic factors may have drastic and long lasting effects.

9. Biosphere level

The part of the Earth inhabited by organisms’ communities is known as the biosphere. It constitutes all ecosystems (areas where living organisms interact with the nonliving components of the environment) and is also called the zone of life on Earth.

Quran and Biology

At many places in the Holy Quran, Allah hints about the origin and characteristics of living organisms. In the same verses, human beings have been instructed to expose the unknown aspects of life, after getting the hints. Here are a few examples of such guidelines.

We know that water makes the 60-70% of the composition of protoplasm of all living things. The above Verse hints at the common origin of all living things in water. As Allah has ordered human beings to think at the hints given by Him, we should study living things so that the mysteries of their origin can be revealed.

In another verse, God says:

“Then fashioned We the drop a clot, then fashioned We the clot a little lump, then fashioned We the little lump bones, then clotted the bones with flesh” (Sura: Al-Mominoon, Verse: 14)

When we think at the hints given in both these Verses, we find the events that occurred in the creation of human beings. Allah also hints at the method of the development of animals including human beings.

This Verse describes the common origin and modification of organisms and also supports the modern concepts of classification. Thus, Quran hints not only at the origin and development of life but also at many characteristics of living organisms.

Careers In Biology

It is essential that students of today, who will occupy positions of leadership tomorrow, have the background of the modern and forward-looking branches of science. An accurate and modern knowledge of biology, will promote a comprehension of both science and scientific research projects. It will benefit the learners in diverse list of careers. The following are the careers that a student of biology can plan to adopt.

Medicine / Surgery:

The profession of medicine deals with the diagnosis and treatment of diseases in human. In surgery the parts of the body may be repaired, replaced or removed, for example the removal of stones through renal surgery, transplantation of kidney, liver etc. Both these professions are studied in the same basic course (MBBS) and then students go for specializations.


Fisheries is the professional study of fish production. There are departments in Pakistan where professionals of fisheries are employed. They serve for enhancing the quality and quantity of fish production. In Pakistan, this profession can be adopted after the bachelor or masters level study of zoology and fisheries.


This profession deals with the food crops and animals which are the source of food. An agriculturist works for the betterment of crops like wheat, rice, corn etc and animals like buffalo cow etc from which we get food. In Pakistan there are many universities which offer professional courses on agriculture after the higher secondary education in biology.

Animal husbandry:

It is the branch of agriculture concerned with the care and breeding of domestic animals (livestock) e.g. cattle, sheep etc. Professional courses in animal husbandry can be adopted after the higher secondary education in biology.


It deals with the art of gardening. A horticulturist works for the betterment of existing varieties and for the production of new varieties of ornamental plants and fruit plants. Biology students can adopt this profession after their higher secondary education.


It deals with the development and maintenance of different types of farm. For example in some farms animal breeding technologies are used for the production of animals which are better protein and milk source. In poultry farms chicken and eggs are produced. Similarly in fruit farms, different fruit yielding plants are grown. A student who has gone through the professional course of agriculture, animal husbandry or fisheries etc. can adopt this profession.


In forestry, professionals look after natural forests and advises to the government for planting and growing artificial forests. Many universities offer professional courses in forestry after the higher secondary education in biology or after bachelor level study of zoology and botany.


It is the latest profession in the field of biology. Biotechnologists study and work for the production of useful products through microorganisms. Universities offer courses in biotechnology after the higher secondary education in biology and after the bachelor level studies of botany or zoology.

Relationship of Biology to other Sciences

The interrelationship among different branches of science cannot be denied. Biology includes information on various aspects of living things but this information relate to the other branches of science as well. Each branch of science has a relationship with all other branches. For example, when studying the process of movement in animals, the biologists have to refer to the laws of motion in physics. This forms the basis of interdisciplinary sciences.


It deals with the study of the principles of physics, which are applicable to biological phenomena. For example, there is a similarity between the working principles of lever in physics and limbs of animals in biology.


It deals with the study of the chemistry of different compounds and processes occurring in living organisms. For example, the study of basic metabolism of photosynthesis and respiration involves the knowledge of chemistry.

Biomathematics / Biometry:

It deals with the study of biological processes using mathematical techniques and tools. For example, to analyze the data gathered after experimental work, biologists have to apply the rules of mathematics.


It deals with study of the occurrence and distribution of different species of living organisms in different geographical regions of the world. It applies the knowledge of the characteristics of particular geographical regions to determine the characteristics of living organisms found there.


It deals with the study of organisms from an economical point of view. For example, the cost value and profit value of the yield of wheat can be calculated through bioeconomics and benefits or losses can be determined